docs: def remainingDays(self, now=None):
          """
          Based on the value of notBefore field, returns the number of
          days the certificate will still be valid. The date used for the
          comparison is the current and local date, as returned by 
          time.localtime(), except if 'now' argument is provided another
          one. 'now' argument can be given as either a time tuple or a string
          representing the date. Accepted format for the string version
          are:
          
           - '%b %d %H:%M:%S %Y %Z' e.g. 'Jan 30 07:38:59 2008 GMT'
           - '%m/%d/%y' e.g. '01/30/08' (less precise)
  
          If the certificate is no more valid at the date considered, then,
          a negative value is returned representing the number of days
          since it has expired.
          
          The number of days is returned as a float to deal with the unlikely
          case of certificates that are still just valid.
          """
          if now is None:
              now = time.localtime()
          elif type(now) is str:
              try:
                  if '/' in now:
                      now = time.strptime(now, '%m/%d/%y')
                  else:
                      now = time.strptime(now, '%b %d %H:%M:%S %Y %Z')
              except:
                  warning("Bad time string provided '%s'. Using current time" % now)
                  now = time.localtime()
  
          now = time.mktime(now)
          nft = time.mktime(self.notAfter)
          diff = (nft - now)/(24.*3600)
          return diff